Funding for this research was provided by:
Japan Society for the Promotion of Science (17H02164)
Received: 24 November 2019
Accepted: 10 March 2020
First Online: 10 April 2020
Ethics approval and consent to participate
: This study was approved by the Institutional Review Board of the Medical School of Tokyo Medical and Dental University, Japan, and Hue University of Medicine and Pharmacy, Vietnam. Permission to recruit junior high school students was obtained from the Department of Education and Training in Thua Thien Hue Province, Vietnam. All of the subjects enrolled in the study agreed to cooperate with the investigators after the purpose of the research had been explained, and written informed consent and assent from parents/guardians and study subjects were obtained.
: Not applicable.
: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.